![]() So if intensity of pixel/area is i = then the replacement character will be char map=" descending and pretend to be linearly distributed.Replace it by character from character map with the closest intensityĪs the character map you can use any characters, but the result gets better if the character has pixels dispersed evenly along the character area.Compute the intensity of each pixel/area.Evenly divide the image into (gray-scale) pixels or (rectangular) areas dots.If you select the dot as a single pixel, the result gets large (one pixel -> single character), so for larger images an area (multiply of font size) is selected instead to preserve the aspect ratio and do not enlarge too much. Intensity-based conversion is great also for gray-scale images (not just black and white). Sometimes for simplicity, the character map can be handled as linearly distributed, causing a slight gamma distortion, usually unseen in the result unless you know what to look for. We need to find intensity closest to the intensity_of(dot) So again if we sorted the map, we can use binary search, otherwise we need an O(n) search minimum distance loop or O(1) dictionary. So we have array of usable characters and their intensities. In other words, when sorted ascending then: intensity_of(map)=intensity_of(map)+constant Īlso when our character map is sorted then we can compute the character directly from intensity (no search needed) character = map Īrbitrary distributed intensity character map So we use only characters which have an intensity difference with the same step. Linearly distributed intensity character map To choose more quickly which character is the best for which intensity, there are two ways: For that we need some list of usable characters, each with a precomputed intensity. The idea is to compute the average gray scale intensity of this dot and then replace it with character with close enough intensity to the computed one. This approach handles each pixel of an area of pixels as a single dot. There are more approaches for image to ASCII art conversion which are mostly based on using mono-spaced fonts. Here is a related Wikipedia page ASCII art (thanks to similar maze to ASCII Art conversion Q&A. keeping it simple (not using too advanced stuff for beginner level programmers). ![]() How can I convert a bitmap image to ASCII art using C++? So I decided to write this Q&A so I can reference such questions directly without rewriting the answer over and over again …Īnother reason is also this meta thread targeted at me so if you got additional input, feel free to comment. ![]() From time to time if the input is good enough for me I decide to respond with an answer and it usually gets a few up-votes per day while active, but then after a few weeks the question gets removed/deleted and all starts from the beginning. I saw many such questions and then silence from the OP (usual low rep) when additional information is requested. This subject pops up here on Stack Overflow from time to time, but it is removed usually because of being a poorly written question. ![]()
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